Neutron Stars

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Transcript of Neutron Stars

Or... How can we describe the force between protons and neutrons in all cases?We are adequately familar with the forces between quarks. The so called color force. Simplistically, there are3 quarks per baryon,Understanding theStrong Force through PulsarsA black hole is supposed to be the densest object in the universe...What is the strong force? and output massesradiienergy densitypressureetc.Observations of neutron starsNuclear saturation density = 2.5 * 10^14 g cm^-3n0 ~ .016/fm^3So at the core of a neutron star, matter is evenmore dense than that in a nucleus!Are glitches the to understanding?A glitch is a rare occurrence in a pulsar when a sudden increase in frequency and decrease in period are detected. The second densest object in our universe is a neutron star. A neutron star is a stellar remnant of astar with an inital mass between 8-30 solar massescore collapse supernova at the end of its nuclear fusion lifeTHE SMALLEST with radii estimated around 10 - 20 km ASKWhat is a neutron star?The residual, color, force is what extends from the nucleons and binds them together. DENSEfrom ~ 10^6 (outer crust) to 10^15 g cm^-3 (core)How dense is neutron star matter?They have been deemed many times as the clocks of the universe. Neutron stars arestellar remants denser than an atomic nucleus at their cores.What is an equation of state (EoS)?SMALL+Diameter: 20-30 km=x 7 billionPulsarsNeutron Star StructureGlitchesWhy do pulsars glitch?The two-component model for glitches describes the pulsar as having two distinct components rotating at different rates.Superfluidity in Helium-32) The faster moving component of the star that transfers its angular momentum to 1.1) The charged component of the star that includes:outer crustinner crust lattice of exotic nucleicore protonselectrons in the starthe neutron superfluid that is spun up in the core by the glitchThe Two Components is at least 1.6% from observations in the Vela pulsar.P as a function of density, temperature and proton fractionWhen the Magnus force overcomes the pinning force on the neutron superfluid in the inner crust, a glitch will occur.What is the neutron star EoS?The Skyrme interaction models the potential energy between neutrons and protons but still has many unknown constants.Input EoS into the Tolman-Oppenheimer-Volkoff (TOV) EquationSkyrmeEoSTolman-Oppenheimer-Volkoff (TOV) EquationProperties of Neutron StarsGNSpropNuclear Symmetry Energyand its slope L Strong Crustal vs. Crustal NeutronsREU 2014By Sabrina BergerEntrainmentWhen will a glitch occur?EntrainmentStrong crustal vs. crustal neutronsThe amount of neutron superfluid in the core actually increasing in its rotational velocity during the glitch. YgVela Pulsar - Credit of NASA/CXC/PSU/G.Pavlov et al. Today's PresentationPulsars and glitchesOur model for glitchesConstraining Yglitch (neutrons coupled during glitch/total star) with mutual frictionConclusionsNow we can talk about the research.

ParametersYgYg is the ratio of neutron superfluid in the core that gets spun up at all during the glitch. can be calculated from the time a glitch takes to spin up the star.Mutual friction?Determining Yg may be possible with better measurements of mutual frictionYg could lead us to a more accurate EoS for extremely dense matterFrom this EoS we could understand the strong force And...The Skyrme interaction models the strong force.Mentor: Dr. William NewtonCalculating G with mutual frictionCalculating Yg with mutual frictionActivity Parameter of the Vela PulsarAcknowledgmentsFor the first time, using observational data from the glitch recovery time, we have been able to constrain Yg (neutrons coupled during glitch/total star). Modeling the glitch using the two component model with realistic equations of state, we do not reproduce the observed glitch activity of the Vela pulsar.of the glitch model?of the equation of stateModification